Device and method for changing the reel in an unwinder

ABSTRACT

To obtain the automatic change of the reel in an unwinder, in particular for reels of paper and other materials in web form, operation in which a reel ( 2 ) that is nearly empty is replaced with a new reel ( 2 ′), wherein provision is made to connect a tail portion (LC) of the web of the nearly empty reel ( 2 ) to the head portion (LT) of the web of the new reel ( 2 ′) after overlapping of said ends (LC) and (LT), said overlap step begins along the surface of the new reel  2 ′, right next to the latter.

The present invention concerns a device and a method for changing thereel in an unwinder, which may be used, in particular, for paper reelsand other materials in web form.

As is known, the function of unwinders is to unwind a web material froma reel to supply it to one or more machines located downstream in adetermined work cycle.

In a possible known conformation, an unwinder comprises a bearingstructure on which are arranged two conical supports intended to engagetwo corresponding mandrels inserted bilaterally in the central tubularnucleus of the paper reel, called also “core”, in such a way that thereel is free to turn around the respective axis and the free unwindingof the respective web is allowed.

A relatively important phase in the use of unwinders is the changing ofthe reel, that is the operation with which a nearly empty reel isreplaced with a new reel. This operation, which must guarantee thecontinuity of the supply of web to the machines located downstream, ismost frequently carried out in an almost exclusively manual way withboth the reels stopped. In practice, the first reel, which is nearlyempty, is moved away from the support cones, between which an operator,with the aid of a mechanical lifter, then fits a new reel to be unwound;the operator must also manually slacken an end portion of the paper websupplied by the nearly empty reel and connect that portion of web to theportion at the start of the web on the new reel. Besides this, theoperator must manually cut the finished web, in a point upstream fromsaid connection.

It is clear that the operation described above is closely linked withthe skill of the operator and, in the event of failed, imprecise orfaulty connection of the webs of the two reels involved, it leads tointerruptions in the production cycle downstream from the unwinder, witheconomic damages due to the resulting production loss. Examples ofmechanical unwinders, in which human intervention is reduced, are givenin WO 2004/080869, WO 2004/080867, WO 2004/043827, U.S. Pat. No.6,679,451 and EP 822912. However, these known unwinders are rathercomplex, from both the mechanical and the functional point of view.

The main aim of the present invention is to overcome the above-mentionedinconveniences, that is to optimise and simplify the reel changingoperation.

This result is achieved, in conformity with the present invention, byadopting the idea of realising a device and a method having thecharacteristics described in the independent claims. Othercharacteristics of the invention are the object of the dependent claims.

Thanks to the present invention, it is possible to change the reelautomatically, precisely and in complete safety, without having toassign this operation to particularly expert or qualified personnel.Moreover, a device in conformity with the present invention isrelatively simple and economic to make, and, in relation to itsmechanical and functional simplicity, it is reliable even after aprolonged period of use.

These and other advantages and characteristics of the present inventionwill be better understood by any technician in the field from thefollowing description, with the aid of the enclosed drawings, given heresimply as a practical example of the invention, but without limiting itin any sense, in which:

FIGS. 1-6 illustrate a possible embodiment of a device in conformitywith the invention, represented in a schematic side view withtransparent parts and others omitted for greater clarity, duringsuccessive operative phases of changing the reel;

FIGS. 7-10 are enlarged details of FIGS. 4, 5 and 6;

FIGS. 11-15 represent another possible embodiment of a device inconformity with the invention, represented in the same way as in FIGS.1-6:

FIGS. 16-18 are enlarged details of FIG. 15;

FIG. 19 schematically represents the device for mechanically joining thewebs coming out of the unwinder illustrated in FIGS. 11-15, seen on aplane at a right angle to the advancing direction of the webs;

FIG. 20 is a simplified block diagram of the connections between some ofthe parts of the present unwinder.

In the enclosed drawings the numerical reference 1 indicates, on thewhole, a possible embodiment of an unwinder according to the presentinvention. In the continuation of this description, the expressions“upstream” and “downstream” refer to the direction of advance of the web(towards the right in the drawings). Moreover, the term “end portion ortail end” defines that portion of the web of a reel that is finishing,obtained by cutting and intended to be joined to the initial portion or“head portion or end” of the web of a reel intended to replace the onethat is finishing.

The unwinder 1 is provided with a pair of conical supports, of the sametype as those used in conventional unwinders, suited to engage twomandrels 50 inserted from opposite sides in the core 3 of a reel 2during the unwinding of the latter, so as to define a horizontal axisaround which the reel itself is free to rotate. In other words, betweensaid support cones is defined an unwinding station of the web suppliedby the reel 2, this station being identified with S1 in the drawings.For simplicity's sake, and as they are known to the technicians in thesector, the aforesaid cones are not illustrated in the drawings.

In FIG. 1, the unwinder 1 is shown in an operative conditioncorresponding to the initial phase of unwinding the reel 2. In FIG. 2,the unwinder 1 is shown in an operative condition corresponding to thepractically complete unwinding of the reel 2. In both cases, the web 4unwound from the reel 2 and drawn downstream by the machines that use it(machines which are of a known type and therefore not described orillustrated in the drawings), passes around a plurality of rollers 6arranged in succession, coming out of the unwinder 1. The axes of saidrollers 6, hereinafter called also exit rollers, are parallel to theaxis of rotation of the reel 2, that is horizontal and situatedtransversely with respect to the web 4.

As contemplated in traditional unwinders, the unwinding station S1comprises a pair of arms 5, usable, as further described below, to moveaway the reel 2 when it is finished. Each arm 5 is hinged, at one of itsends, on a respective side of the base frame 10 of the unwinder, andpresents a shaped part 12 with the profile of an arc of a circleintended to exert a thrust on the mandrels 50 inserted in the core 3 ofthe reel 2 when it must be removed from the station S1. Reference 7indicates a pin which defines the respective hinging axis, which isparallel to the axis around which the reel 2 rotates. On the arm 5, onthe side opposite the pin 7, is hinged the rod 9 of a cylinder 8. Theskirt of the cylinder 8 is fixed to the corresponding side of the frame10 by means of a pin 11. The activation of the cylinder 8, that is theextension of the respective rod 9, determines a rotation of the arm 5around the pin 7 (in a counter-clockwise direction with reference to thedrawings). Said rotation of the arm 5, determined by the activation ofthe cylinder 8, causes the reel 2 to be moved away from the unwindingstation S1 towards a temporary parking station S2, which is at a lowerheight than the unwinding station S1 and is connected to the latter bymeans of an inclined plane 13. In practice, the portion 12 of the arm 5exerts a thrust on the reel 2, bringing the latter onto the inclinedplane 13 where the reel moves, by gravity, until it arrives at thetemporary parking station S2 (see arrow F in FIG. 2) . The temporaryparking station S2 is provided with idle rollers or bearings 29 withparallel axes 290 which interact with the mandrels 50 inserted in thecore 3 making it free to rotate around the respective longitudinal axis300 and allowing the reel 2 to freely rotate despite the transfer of thesame reel 2 from the station S1 to the station S2. Said rollers orbearings 29 are installed at the end of the ramp defined by the inclinedplane 13, with the respective axes parallel to the axis of rotation ofthe reel 2, that is at a right angle to the sides of the aforesaid frame10 and, therefore, transverse with respect to the web 4. In conformitywith the example shown in the figures in the enclosed drawings, on eachside of the frame 10 two rollers 29 are fitted, the axes of which are atdifferent heights to allow the most precise adaptation to the diameterof the core 3.

The unwinder 1 is also provided with a device exhibiting two supportarms 15, which are hinged onto an upper portion of the frame 10, bycorresponding pins 16. The rear end of each arm 15 is interlocked with agear motor 17 which commands its rotation around the axis of therespective pin 16, from and towards the station S1. The distal end 18 ofeach of the arms 15 supports a hook 21 shaped in such a way as tosupport the mandrels 50 inserted in the core 3 of a new reel 2′. Thereel 2′ is taken onto the hooks 21 by means of a bridge crane (alreadyknown and not represented in the drawings) normally available in theplants where the unwinder is used.

Advantageously, on the outer surface of the head end “LT” of the web onthe reel 2′ a means is applied for joining the webs supplied by thereels 2 and 2′; said means may consist, for example, of a piece ofdouble-sided adhesive tape 14 extending along the whole width of the end“LT”, or of a predetermined amount of glue applied along an extent ofthe same length. Preferably the reel 2′ is loaded onto the hooks 21 insuch a way that said end “LT” is on the side of the reel 2′ opposite theone facing the pins 16 of the arms 15 and inside a sector “XY” theprojection of which on the plane 13 is between the stations S1 and S2.

Each hook 21 is hinged onto the distal end 18 of the respective arm 15and on it acts the rod 24 of a cylinder 22, the skirt of which is hingedon the arm 15 in a point indicated with 23. For simplicity's sake, saidcylinder 22 is shown only in FIG. 14.

As said above, the activation of the gear motor 17 determines a rotationof the arms 15 around the pins 16. Said rotation corresponds to alowering of the reel 2′ supported by the hooks 21, that is a shifttowards the unwinding station S1 where the reel 2′ is passed to the arms5. The activation of the cylinder 22, with a retraction of its rod 24,determines a rotation of the respective hook 21 (counter-clockwise inthe drawings), allowing the release of the hook and the return of thearms 15 into the initial raised position.

of course, in the phases of moving a reel away from the station S1 andreplacing it with a new reel, the aforesaid cones are open, that isreleased from the respective mandrels 50, while they are arranged in aposition to engage the mandrels 50 only after a reel has beendefinitively positioned in the station S1.

The unwinding station S1 is also provided, as in unwinders of the knowntype, with a pair of belts 25, located at a predetermined distance andparallel to each other so as to interact with two corresponding edges ofthe reel during unwinding. The belts 25 are closed in a loop onrespective rollers 27 and they are driven in a known way. Also acting onthem is a device 26 of a known type for taking up tension. In practice,when working the belts 25 are constantly stretched tight so as topresent, on the part facing the unwinding station, that is in temporarycontact with the reel placed in the station S1, an extensioncorresponding to the arc of circumference temporarily defined by thereel being unwound.

FIG. 3 shows a phase of the reel changing operation, in which the reel 2is empty and is suitable freed from the cones after the belts 25 havebeen slackened on a command given by the control unit “C” describedbelow. In this condition, the reel 2 is pushed (towards the left in thefigure) by the arms 5 and arrives at the station S2, while the new reel2′ to be unwound is supported by the hooks 21 on the arms 15. The web 4of the reel 2 is represented as a straight line that connects thestation S2 to the first of the output rollers 6. Said roller 6 islocated opposite a pressing element 30 which presents a longitudinalextension corresponding to the width of the web 4. In other words, thepresser 30 is situated and acts transversely with respect to the web 4.

FIG. 4 shows the phase in which the new reel 2′ has been placed in theunwinding station S1 (the belts 25 are stopped).

Next (FIG. 5) the belts 25 are reactivated, causing the rotation of thereel 2′. Of course, before reactivating the belts 25 the aforesaid conesare introduced in the mandrels 50 of the reel 2′.

The positioning of the reel 2′ in the station S1 determines theinteraction of the same reel 2′ with the web 4 that is going downstream.In other words, as it goes down, the reel 2′ intercepts the web 4 comingfrom the reel 2 and the web 4 is automatically subject to looseningunder the weight of the reel 2′, because the rollers or bearings 29allow the free rotation of the reel 2 around its own axis in the stationS2. The detail in FIG. 7 shows the head portion “LT” of the web of thereel 2′ which rests on the end portion of the web coming from the reel 2located in the station S2.

Once the reel 2′ has been positioned in the station S1 and the belts 25have been reactivated, so that the reel 2′ starts rotating, the web onthe reel 2 is pulled forward, since it is between the belts 25 and thereel 2′.

The contact between the end “LT” suitably positioned for joining (forexample with double-sided adhesive tape 14 or glued) and the web 4 goingdownstream determines the connection between the webs of reel 2 and reel2′. The initial connecting phase is illustrated in FIG. 5 and in greaterdetail in FIG. 9. Since the surface of the reel 2′ is in contact withthe belts 25, effective gluing between the two webs is carried out inthe points of contact. The presence of said presser 30, which acts onthe whole width of the outgoing web, determines a perfect adhesion alongthe whole width of the webs thus connected. FIG. 6 and in greater detailFIG. 10, show the aforesaid head portions “LT” and end portions “LC”shortly before arriving at the presser 30. Said presser 30 may consist,for example, of a rubber roller fitted next to the first exit roller 6,with the axis parallel to and facing the axis of the latter, on acorresponding pair of arms 37 hinged on the aforesaid frame 10 andinterlocked with an actuator 36 that commands their rotation around theaxes of the respective hinges 38 so as to obtain, on command of the unitC mentioned below, the moving of the roller 30 towards the opposite exitroller 6 and, vice versa, its moving away. In this way, it is possibleto activate the presser 30 in time with the transit of the joining lineof the two webs and deactivate it afterwards, by moving the roller 30away from the said first exit roller 6.

The unwinder 1 also comprises a cutting device 28, the action of whichis shown in FIG. 5 and which is illustrated in greater detail in FIG. 8.In practice, the cutting device 28 cuts the web 4 of the reel 2 upstreamfrom the point of joining with the end “LT” of the web of the reel 2′,determining the formation of the tail end “LC” of the web supplied bythe nearly empty reel 2. The cutting device 28 comprises, in the exampleshown in FIG. 8, a blade 32 supported by the distal end of an arm 31,the proximal end of which is radially fixed to a shaft 33 with axisparallel to the width of the web. The rotation of the shaft 33(counter-clockwise rotation in the figure) determines the interventionof the blade 32, which extends for such a length as to allow the cuttingof the web 4 on its entire width.

The tail end “LC” and the head end “LT” of the webs suppliedrespectively by the reels 2 and 2′ overlap while they are both moving,that is directed towards the exit or output of the unwinder. More inparticular, as may be seen in the detail in FIG. 9, said overlap beginsalong the surface of the reel 2′, that is right next to it.

The control of the cutting means 28 may be programmed to cut the web ofthe finishing reel 2 in a stage in time after that of said overlap andalso in a previous phase (for example with relation to the length of theplane 13, that is to say the distance between the stations S1 and S2).In the first case, said overlap takes place while both the reels 2 and2′ are rotating about their respective axes. In the second case, saidoverlap takes place while only the reel 2′ is rotating, the reel 2 beingstopped in the station S2 due to cutting of the respective web and,therefore, not being subject to any action that determines its rotation.

The empty reel is then moved away using the bridge crane mentionedabove.

FIGS. 11-19 in the enclosed drawings concern a further embodiment of thepresent unwinder; in these figures, the elements the same as those inFIGS. 1-10 have the same alphanumeric references. In the example shownin FIGS. 11-19, a different mechanism is provided for joining the tailend “LC” and the head end “LT” of the webs supplied by the reels 2 and2′. The phases of replacing the empty reel 2 with a new reel 2′ and ofoverlapping said ends “LC” and “LT” take place as described above withreference to FIGS. 1-10. More particularly, said join is realizedmechanically, rather than by gluing, by means of a ply-bonding unit 90fitted in place of the presser 30. The wheels 91 of the unit 90 areinterlocked with a corresponding actuator 92 which commands theirmovement from and towards the roller 6 below: when the aforesaid ends“LC” and “LT” are close to the unit 90, this is activated by theactuator 92, bringing the wheels 91 close to the roller 6 below and itis deactivated after a predetermined time, once the mechanical union ofthe two ends has been realized, with detachment of the wheels 91 fromthe roller 6. Immediately upstream from the ply-bonding unit 90 isfitted a suction plane 95 which facilitates and guides the exit of theends “LC” and “LT” to be joined. Said plane 95 is fitted rotating on acorresponding horizontal axis 96, that is transverse to the web andparallel to the axes of rotation of the reels 2 and 2′, commanded by acorresponding actuator 97 anchored to the frame 10. The actuator 97determines the rotation of the plane 95 around the axis 96 (clockwiserotation in the figure) to adapt its position to the diameter of thereel located in the station S1 as shown schematically in FIG. 18. Inpractice, the suction plane 95 is at a tangent to the reel present inthe station S1, irrespective of its diameter, and it realizes anefficient means for guiding the material in web form towards theply-bonding unit 90. Advantageously, suction on the plane 95 isactivated at the same time as the cutting means 28 and is maintained fora predetermined time. Said plane 95 is interlocked with a suction device98 (shown only in the block diagram in FIG. 20). Of course the suctionis of such an extent as to allow the adhesion of the material in webform on the plane 95 but without preventing its advance towards theply-bonding unit 90.

The movements and commands of the various elements may be managedautomatically by means of a programmable electronic control unit C, ofthe type known to industrial automation technicians and, therefore,represented only schematically in FIG. 20. In particular, the controlunit C is connected to a sensor 34 located in the unwinding station S1and apt to detect the diameter of the reel in the same station. By meansof the sensor 34 it is possible to coordinate the movement of thevarious parts, such as, for example the cones that support the reel,identified with number 35 in FIG. 20, the cylinders 8 and 22, the gearmotor 17, the tensioning device 26 for the belt 25, the cutting device28, the ply-bonding unit 90, the aforementioned suction unit 98 and theactuator 36 of the presser 30. The control unit “C” also commands thestopping and restarting phases of the machines interlocked with theunwinder, that is to say, the machines receiving the webs unwound fromsaid reels.

The machine described above allows a rapid and easy passage from theunwinding of one reel to that of the next reel, guaranteeing high safetyand speed in the connection of the webs of the two reels and maximumsafety for operators.

It is understood that the drawings show only a possible embodiment ofthe invention, the forms and configurations of which may vary withouthowever departing from the idea underlying the invention.

1. Method for automatically changing the reel in an unwinder, inparticular for reels of paper and other materials in web form, operationin which a reel (2) that is nearly empty is replaced with a new reel(2′), wherein provision is made to connect a tail portion (LC) of theweb of the nearly empty reel (2) to the head portion (LT) of the web ofthe new reel (2′) after overlapping of said ends (LC) and (LT),characterized in that said overlap step begins along the surface of thenew reel 2′, right next to the latter.
 2. Method according to claim 1characterized in that said ends (LC) and (LT) overlap while both aremoving, directed towards a web exit section of the unwinder.
 3. Methodaccording to claim 1 characterized in that said overlap takes placewhile at least one of said reels is rotating about the respective axis.4. Method according to claim 3 characterized in that both said reelsrotate about their axes before said overlap step begins.
 5. Methodaccording to claim 1 characterized in that during the substitution ofthe reel (2) that is nearly empty with the new reel (2′) the latterintercepts a tail portion (4) of reel (2) that is nearly empty. 6.Method according to claim 1 characterized in that an adhesive means (14)is applied to said head portion (LT) of the web of the new reel (2′)before the connection thereof with the tail portion (4) of the reel (2)that is nearly empty takes place.
 7. Method according to claim 1characterized in that a mechanical connection is realized between saidportions (LC) and (LT) by means of ply-bonding.
 8. Method according toclaim 1 characterized in that the web (4) unwound from the reel (2) thatis nearly empty is subject to loosening due to the weight of the newreel (2′) while the latter is positioned in an operative station (S1)previously engaged by the reel (2) that is nearly empty and further dueto the free and concurrent rotation of the reel (2) that is nearly emptypositioned in a temporary parking station.
 9. Method according to claim1 characterized in that the web (4) unwound from the reel (2) that isnearly empty is subject to cut at a point upstream of said connection.10. Device for automatically changing the reel in an unwinder, inparticular for reels of paper and other materials in web form, of thetype comprising an unwinding station wherein a reel freely rotates aboutthe longitudinal axis (300) of the respective core (30), thus beingunwound to feed the respective web material downstream, a temporaryparking station (S2) provided upstream of said unwinding station (S1)wherein reels (2) that are nearly empty are positioned and means fortransferring the reels (2) that are nearly empty from said unwindingstation (S1) to said parking station (S2), characterized in that itcomprises a plurality of idle rollers or bearings (29) which aredisposed in said parking station (S2) with their axes (290) parallel tothe axis (300) of the core (30) of the reel (2) that is nearly empty.11. Device according to claim 10 characterized in that said rollers orbearings (29) are provided, in correspondence of said parking station(S2), at the end of a ramp defined by an inclined plane (13) connectingsaid unwinding station (S1) with said parking station (S2).
 12. Deviceaccording to claim 10 characterized in that it comprises automaticcutting means disposed and acting between said parking station (S2) andsaid unwinding station (S1), said cutting means being intended to cutthe web (4) provided by the reel (2) that is nearly empty.
 13. Deviceaccording to claim 10 characterized in that it comprises pressure means(30), provided downstream of said unwinding station (S1), indeed toexert a pressure onto glued portions of the webs provided by the reelthat is nearly empty and the new reel, said pressure being exerted alongthe transverse direction of the webs, said portions being a tail portionof the web (4) unwound from the reel (2) that is nearly empty and a headportion of the new reel (2′).
 14. Device according to claim 10characterized in that it comprises for mechanically joining the tailportion of the web unwound from the reel (2) that is nearly empty andthe head portion of the new reel.
 15. Device according to claim 14characterized in that it means for guiding said tail and head portionsdirected towards said mechanically joining means.
 16. Device accordingto claim 12 characterized in that it comprises a control unit (C) towhich said cutting means are connected.